Method and device for operating ue pertaining to bsr in wireless communication system

ABSTRACT

An embodiment relates to a method for operating a transmitting user equipment (TX UE) in a wireless communication system, the method including: a step in which the TX UE requests a base station for a sidelink resource through a first beam; and a step in which the TX UE triggers first buffer status reporting (BSR), wherein the TX UE cancels the first BSR on the basis of a beam failure recovery (BFR) trigger pertaining to the first beam.

TECHNICAL FIELD

The present disclosure relates to a wireless communication system, andmore particularly, to a method and apparatus for operating a userequipment (UE) in relation to beam failure recovery (BFR) and bufferstatus reporting (BSR).

BACKGROUND ART

Wireless communication systems have been widely deployed to providevarious types of communication services such as voice or data. Ingeneral, a wireless communication system is a multiple access systemthat supports communication of multiple users by sharing availablesystem resources (a bandwidth, transmission power, etc.). Examples ofmultiple access systems include a code division multiple access (CDMA)system, a frequency division multiple access (FDMA) system, a timedivision multiple access (TDMA) system, an orthogonal frequency divisionmultiple access (OFDMA) system, a single carrier frequency divisionmultiple access (SC-FDMA) system, and a multi carrier frequency divisionmultiple access (MC-FDMA) system.

A wireless communication system uses various radio access technologies(RATs) such as long term evolution (LTE), LTE-advanced (LTE-A), andwireless fidelity (WiFi). 5th generation (5G) is such a wirelesscommunication system. Three key requirement areas of 5G include (1)enhanced mobile broadband (eMBB), (2) massive machine type communication(mMTC), and (3) ultra-reliable and low latency communications (URLLC).Some use cases may require multiple dimensions for optimization, whileothers may focus only on one key performance indicator (KPI). 5Gsupports such diverse use cases in a flexible and reliable way.

eMBB goes far beyond basic mobile Internet access and covers richinteractive work, media and entertainment applications in the cloud oraugmented reality (AR). Data is one of the key drivers for 5G and in the5G era, we may for the first time see no dedicated voice service. In 5G,voice is expected to be handled as an application program, simply usingdata connectivity provided by a communication system. The main driversfor an increased traffic volume are the increase in the size of contentand the number of applications requiring high data rates. Streamingservices (audio and video), interactive video, and mobile Internetconnectivity will continue to be used more broadly as more devicesconnect to the Internet. Many of these applications require always-onconnectivity to push real time information and notifications to users.Cloud storage and applications are rapidly increasing for mobilecommunication platforms. This is applicable for both work andentertainment. Cloud storage is one particular use case driving thegrowth of uplink data rates. 5G will also be used for remote work in thecloud which, when done with tactile interfaces, requires much lowerend-to-end latencies in order to maintain a good user experience.Entertainment, for example, cloud gaming and video streaming, is anotherkey driver for the increasing need for mobile broadband capacity.Entertainment will be very essential on smart phones and tabletseverywhere, including high mobility environments such as trains, carsand airplanes. Another use case is augmented reality (AR) forentertainment and information search, which requires very low latenciesand significant instant data volumes.

One of the most expected 5G use cases is the functionality of activelyconnecting embedded sensors in every field, that is, mMTC. It isexpected that there will be 20.4 billion potential Internet of things(IoT) devices by 2020. In industrial IoT, 5G is one of areas that playkey roles in enabling smart city, asset tracking, smart utility,agriculture, and security infrastructure.

URLLC includes services which will transform industries withultra-reliable/available, low latency links such as remote control ofcritical infrastructure and self-driving vehicles. The level ofreliability and latency are vital to smart-grid control, industrialautomation, robotics, drone control and coordination, and so on.

Now, multiple use cases will be described in detail.

5G may complement fiber-to-the home (FTTH) and cable-based broadband (ordata-over-cable service interface specifications (DOCSIS)) as a means ofproviding streams at data rates of hundreds of megabits per second togiga bits per second. Such a high speed is required for TV broadcasts ator above a resolution of 4K (6K, 8K, and higher) as well as virtualreality (VR) and AR. VR and AR applications mostly include immersivesport games. A special network configuration may be required for aspecific application program. For VR games, for example, game companiesmay have to integrate a core server with an edge network server of anetwork operator in order to minimize latency.

The automotive sector is expected to be a very important new driver for5G, with many use cases for mobile communications for vehicles. Forexample, entertainment for passengers requires simultaneous highcapacity and high mobility mobile broadband, because future users willexpect to continue their good quality connection independent of theirlocation and speed. Other use cases for the automotive sector are ARdashboards. These display overlay information on top of what a driver isseeing through the front window, identifying objects in the dark andtelling the driver about the distances and movements of the objects. Inthe future, wireless modules will enable communication between vehiclesthemselves, information exchange between vehicles and supportinginfrastructure and between vehicles and other connected devices (e.g.,those carried by pedestrians). Safety systems may guide drivers onalternative courses of action to allow them to drive more safely andlower the risks of accidents. The next stage will be remote-controlledor self-driving vehicles. These require very reliable, very fastcommunication between different self-driving vehicles and betweenvehicles and infrastructure. In the future, self-driving vehicles willexecute all driving activities, while drivers are focusing on trafficabnormality elusive to the vehicles themselves. The technicalrequirements for self-driving vehicles call for ultra-low latencies andultra-high reliability, increasing traffic safety to levels humanscannot achieve.

Smart cities and smart homes, often referred to as smart society, willbe embedded with dense wireless sensor networks. Distributed networks ofintelligent sensors will identify conditions for cost- andenergy-efficient maintenance of the city or home. A similar setup can bedone for each home, where temperature sensors, window and heatingcontrollers, burglar alarms, and home appliances are all connectedwirelessly. Many of these sensors are typically characterized by lowdata rate, low power, and low cost, but for example, real time highdefinition (HD) video may be required in some types of devices forsurveillance.

The consumption and distribution of energy, including heat or gas, isbecoming highly decentralized, creating the need for automated controlof a very distributed sensor network. A smart grid interconnects suchsensors, using digital information and communications technology togather and act on information. This information may include informationabout the behaviors of suppliers and consumers, allowing the smart gridto improve the efficiency, reliability, economics and sustainability ofthe production and distribution of fuels such as electricity in anautomated fashion. A smart grid may be seen as another sensor networkwith low delays.

The health sector has many applications that may benefit from mobilecommunications. Communications systems enable telemedicine, whichprovides clinical health care at a distance. It helps eliminate distancebarriers and may improve access to medical services that would often notbe consistently available in distant rural communities. It is also usedto save lives in critical care and emergency situations. Wireless sensornetworks based on mobile communication may provide remote monitoring andsensors for parameters such as heart rate and blood pressure.

Wireless and mobile communications are becoming increasingly importantfor industrial applications. Wires are expensive to install andmaintain, and the possibility of replacing cables with reconfigurablewireless links is a tempting opportunity for many industries. However,achieving this requires that the wireless connection works with asimilar delay, reliability and capacity as cables and that itsmanagement is simplified. Low delays and very low error probabilitiesare new requirements that need to be addressed with 5G

Finally, logistics and freight tracking are important use cases formobile communications that enable the tracking of inventory and packageswherever they are by using location-based information systems. Thelogistics and freight tracking use cases typically require lower datarates but need wide coverage and reliable location information.

A wireless communication system is a multiple access system thatsupports communication of multiple users by sharing available systemresources (a bandwidth, transmission power, etc.). Examples of multipleaccess systems include a CDMA system, an FDMA system, a TDMA system, anOFDMA system, an SC-FDMA system, and an MC-FDMA system.

Sidelink (SL) refers to a communication scheme in which a direct link isestablished between user equipments (UEs) and the UEs directly exchangevoice or data without intervention of a base station (BS). SL isconsidered as a solution of relieving the BS of the constraint ofrapidly growing data traffic.

Vehicle-to-everything (V2X) is a communication technology in which avehicle exchanges information with another vehicle, a pedestrian, andinfrastructure by wired/wireless communication. V2X may be categorizedinto four types: vehicle-to-vehicle (V2V), vehicle-to-infrastructure(V2I), vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). V2Xcommunication may be provided via a PC5 interface and/or a Uu interface.

As more and more communication devices demand larger communicationcapacities, there is a need for enhanced mobile broadband communicationrelative to existing RATs. Accordingly, a communication system is underdiscussion, for which services or UEs sensitive to reliability andlatency are considered. The next-generation RAT in which eMBB, MTC, andURLLC are considered is referred to as new RAT or NR. In NR, V2Xcommunication may also be supported.

FIG. 1 is a diagram illustrating V2X communication based on pre-NR RATand V2X communication based on NR in comparison.

For V2X communication, a technique of providing safety service based onV2X messages such as basic safety message (BSM), cooperative awarenessmessage (CAM), and decentralized environmental notification message(DENM) was mainly discussed in the pre-NR RAT. The V2X message mayinclude location information, dynamic information, and attributeinformation. For example, a UE may transmit a CAM of a periodic messagetype and/or a DENM of an event-triggered type to another UE.

For example, the CAM may include basic vehicle information includingdynamic state information such as a direction and a speed, vehiclestatic data such as dimensions, an external lighting state, pathdetails, and so on. For example, the UE may broadcast the CAM which mayhave a latency less than 100 ms. For example, when an unexpectedincident occurs, such as breakage or an accident of a vehicle, the UEmay generate the DENM and transmit the DENM to another UE. For example,all vehicles within the transmission range of the UE may receive the CAMand/or the DENM. In this case, the DENM may have priority over the CAM.

In relation to V2X communication, various V2X scenarios are presented inNR. For example, the V2X scenarios include vehicle platooning, advanceddriving, extended sensors, and remote driving.

For example, vehicles may be dynamically grouped and travel togetherbased on vehicle platooning. For example, to perform platoon operationsbased on vehicle platooning, the vehicles of the group may receiveperiodic data from a leading vehicle. For example, the vehicles of thegroup may widen or narrow their gaps based on the periodic data.

For example, a vehicle may be semi-automated or full-automated based onadvanced driving. For example, each vehicle may adjust a trajectory ormaneuvering based on data obtained from a nearby vehicle and/or a nearbylogical entity. For example, each vehicle may also share a dividingintention with nearby vehicles.

Based on extended sensors, for example, raw or processed data obtainedthrough local sensor or live video data may be exchanged betweenvehicles, logical entities, terminals of pedestrians and/or V2Xapplication servers. Accordingly, a vehicle may perceive an advancedenvironment relative to an environment perceivable by its sensor.

Based on remote driving, for example, a remote driver or a V2Xapplication may operate or control a remote vehicle on behalf of aperson incapable of driving or in a dangerous environment. For example,when a path may be predicted as in public transportation, cloudcomputing-based driving may be used in operating or controlling theremote vehicle. For example, access to a cloud-based back-end serviceplatform may also be used for remote driving.

A scheme of specifying service requirements for various V2X scenariosincluding vehicle platooning, advanced driving, extended sensors, andremote driving is under discussion in NR-based V2X communication.

DISCLOSURE Technical Problem

The object of embodiment(s) is to provide a method of processing currentbuffer status reporting (BSR) when beam failure recovery (BFR) istriggered.

Technical Solution

In an aspect of the present disclosure, a method of operating atransmitting user equipment (TX UE) in a wireless communication systemis provided. The method may include: transmitting, by the TX UE, arequest for a sidelink resource to a base station (BS) on a first beam;and triggering, by the TX UE, first buffer status reporting (BSR). TheTX UE may cancel the first BSR based on triggering of beam failurerecovery (BFR) related to the first beam.

In another aspect of the present disclosure, a TX UE is provided. The TXUE may include: at least one processor; and at least one computer memoryoperably connected to the at least one processor and configured to storeinstructions that, when executed, cause the at least one processor toperform operations. The operations may include: transmitting, by the TXUE, a request for a sidelink resource to a BS on a first beam; andtriggering, by the TX UE, first BSR. The TX UE may cancel the first BSRbased on triggering of BFR related to the first beam.

In still another aspect of the present disclosure, a processorconfigured to perform operations for a TX UE in a wireless communicationsystem is provided. The operations may include: transmitting, by the TXUE, a request for a sidelink resource to a BS on a first beam; andtriggering, by the TX UE, first BSR. The TX UE may cancel the first BSRbased on triggering of BFR related to the first beam.

In a further aspect of the present disclosure, a computer-readablestorage medium configured to store at least one computer programincluding instructions that, when executed by at least one processor,cause the at least one processor to perform operations for a userequipment (UE). The operations may include: transmitting, by a TX UE, arequest for a sidelink resource to a BS on a first beam; and triggering,by the TX UE, first BSR. The TX UE may cancel the first BSR based ontriggering of BFR related to the first beam.

The TX UE may trigger second BSR for first sidelink data related to thefirst BSR based on selection of a second beam by the BFR.

The TX UE may transmit the second BSR to the BS on the second beam.

The first BSR may occur before the triggering of the BFR.

Based on occurrence of second sidelink data, which is different from thefirst sidelink data related to the first BSR, after the triggering ofthe BFR, the TX UE may trigger third BSR by aggregating BSR informationfor the first sidelink data and BSR information for the second sidelinkdata.

The first sidelink data and the second sidelink data may be related to asame destination identifier (ID).

The first BSR may be based on occurrence of first sidelink data to betransmitted by the TX UE to a receiving user equipment (RX UE).

A cell at a time that the first BSR is triggered may be different from acell at a time that beam recovery (BFR?) is terminated.

The BFR may be triggered based on detection of beam failure by the TX UEmore than a predetermined number of times.

A BFR timer may start upon the triggering of the BFR.

The TX UE may be a Mode 1 UE.

The TX UE may communicate with at least one of another UE, a UE or BSrelated to autonomous vehicles, or a network.

Advantageous Effects

According to embodiment(s), buffer status reporting (BSR) may beefficiently processed in consideration of sidelink characteristics.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the disclosure andtogether with the description serve to explain the principle of thedisclosure. In the drawings:

FIG. 1 is a diagram comparing vehicle-to-everything (V2X) communicationbased on pre-new radio access technology (pre-NR) with V2X communicationbased on NR;

FIG. 2 is a diagram illustrating the structure of a long term evolution(LTE) system according to an embodiment of the present disclosure;

FIG. 3 is a diagram illustrating user-plane and control-plane radioprotocol architectures according to an embodiment of the presentdisclosure;

FIG. 4 is a diagram illustrating the structure of an NR system accordingto an embodiment of the present disclosure;

FIG. 5 is a diagram illustrating functional split between a nextgeneration radio access network (NG-RAN) and a 5th generation corenetwork (5GC) according to an embodiment of the present disclosure;

FIG. 6 is a diagram illustrating the structure of an NR radio frame towhich embodiment(s) of the present disclosure is applicable;

FIG. 7 is a diagram illustrating a slot structure of an NR frameaccording to an embodiment of the present disclosure;

FIG. 8 is a diagram illustrating radio protocol architectures forsidelink (SL) communication according to an embodiment of the presentdisclosure;

FIG. 9 is a diagram illustrating radio protocol architectures for SLcommunication according to an embodiment of the present disclosure;

FIG. 10 illustrates a synchronization source or synchronizationreference in V2X according to an embodiment of the present disclosure.

FIGS. 11 to 13 are diagrams for explaining embodiment(s) of the presentdisclosure.

FIGS. 14 to 20 are diagrams for explaining various devices to whichembodiment(s) of the present disclosure are applicable.

BEST MODE

In various embodiments of the present disclosure, “/” and “,” should beinterpreted as “and/or”. For example, “A/B” may mean “A and/or B”.Further, “A, B” may mean “A and/or B”. Further, “A/B/C” may mean “atleast one of A, B and/or C”. Further, “A, B, C” may mean “at least oneof A, B and/or C”.

In various embodiments of the present disclosure, “or” should beinterpreted as “and/or”. For example, “A or B” may include “only A”,“only B”, and/or “both A and B”. In other words, “or” should beinterpreted as “additionally or alternatively”.

Techniques described herein may be used in various wireless accesssystems such as code division multiple access (CDMA), frequency divisionmultiple access (FDMA), time division multiple access (TDMA), orthogonalfrequency division multiple access (OFDMA), single carrier-frequencydivision multiple access (SC-FDMA), and so on. CDMA may be implementedas a radio technology such as universal terrestrial radio access (UTRA)or CDMA2000. TDMA may be implemented as a radio technology such asglobal system for mobile communications (GSM)/general packet radioservice (GPRS)/Enhanced Data Rates for GSM Evolution (EDGE). OFDMA maybe implemented as a radio technology such as IEEE 802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE 802.20, evolved-UTRA (E-UTRA), or the like. IEEE802.16m is an evolution of IEEE 802.16e, offering backward compatibilitywith an IRRR 802.16e-based system. UTRA is a part of universal mobiletelecommunications system (UMTS). 3rd generation partnership project(3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS)using evolved UTRA (E-UTRA). 3GPP LTE employs OFDMA for downlink (DL)and SC-FDMA for uplink (UL). LTE-advanced (LTE-A) is an evolution of3GPP LTE.

A successor to LTE-A, 5^(th) generation (5G) new radio access technology(NR) is a new clean-state mobile communication system characterized byhigh performance, low latency, and high availability. 5G NR may use allavailable spectral resources including a low frequency band below 1 GHz,an intermediate frequency band between 1 GHz and 10 GHz, and a highfrequency (millimeter) band of 24 GHz or above.

While the following description is given mainly in the context of LTE-Aor 5G NR for the clarity of description, the technical idea of anembodiment of the present disclosure is not limited thereto.

FIG. 2 illustrates the structure of an LTE system according to anembodiment of the present disclosure. This may also be called an evolvedUMTS terrestrial radio access network (E-UTRAN) or LTE/LTE-A system.

Referring to FIG. 2, the E-UTRAN includes evolved Node Bs (eNBs) 20which provide a control plane and a user plane to UEs 10. A UE 10 may befixed or mobile, and may also be referred to as a mobile station (MS),user terminal (UT), subscriber station (SS), mobile terminal (MT), orwireless device. An eNB 20 is a fixed station communication with the UE10 and may also be referred to as a base station (BS), a basetransceiver system (BTS), or an access point.

eNBs 20 may be connected to each other via an X2 interface. An eNB 20 isconnected to an evolved packet core (EPC) 39 via an S1 interface. Morespecifically, the eNB 20 is connected to a mobility management entity(MME) via an S1-MME interface and to a serving gateway (S-GW) via anS1-U interface.

The EPC 30 includes an MME, an S-GW, and a packet data network-gateway(P-GW). The MME has access information or capability information aboutUEs, which are mainly used for mobility management of the UEs. The S-GWis a gateway having the E-UTRAN as an end point, and the P-GW is agateway having a packet data network (PDN) as an end point.

Based on the lowest three layers of the open system interconnection(OSI) reference model known in communication systems, the radio protocolstack between a UE and a network may be divided into Layer 1 (L1), Layer2 (L2) and Layer 3 (L3). These layers are defined in pairs between a UEand an Evolved UTRAN (E-UTRAN), for data transmission via the Uuinterface. The physical (PHY) layer at L1 provides an informationtransfer service on physical channels. The radio resource control (RRC)layer at L3 functions to control radio resources between the UE and thenetwork. For this purpose, the RRC layer exchanges RRC messages betweenthe UE and an eNB.

FIG. 3(a) illustrates a user-plane radio protocol architecture accordingto an embodiment of the disclosure.

FIG. 3(b) illustrates a control-plane radio protocol architectureaccording to an embodiment of the disclosure. A user plane is a protocolstack for user data transmission, and a control plane is a protocolstack for control signal transmission.

Referring to FIGS. 3(a) and 3(b), the PHY layer provides an informationtransfer service to its higher layer on physical channels. The PHY layeris connected to the medium access control (MAC) layer through transportchannels and data is transferred between the MAC layer and the PHY layeron the transport channels. The transport channels are divided accordingto features with which data is transmitted via a radio interface.

Data is transmitted on physical channels between different PHY layers,that is, the PHY layers of a transmitter and a receiver. The physicalchannels may be modulated in orthogonal frequency division multiplexing(OFDM) and use time and frequencies as radio resources.

The MAC layer provides services to a higher layer, radio link control(RLC) on logical channels. The MAC layer provides a function of mappingfrom a plurality of logical channels to a plurality of transportchannels. Further, the MAC layer provides a logical channel multiplexingfunction by mapping a plurality of logical channels to a singletransport channel. A MAC sublayer provides a data transmission serviceon the logical channels.

The RLC layer performs concatenation, segmentation, and reassembly forRLC serving data units (SDUs). In order to guarantee various quality ofservice (QoS) requirements of each radio bearer (RB), the RLC layerprovides three operation modes, transparent mode (TM), unacknowledgedmode (UM), and acknowledged Mode (AM). An AM RLC provides errorcorrection through automatic repeat request (ARQ).

The RRC layer is defined only in the control plane and controls logicalchannels, transport channels, and physical channels in relation toconfiguration, reconfiguration, and release of RBs. An RB refers to alogical path provided by L1 (the PHY layer) and L2 (the MAC layer, theRLC layer, and the packet data convergence protocol (PDCP) layer), fordata transmission between the UE and the network.

The user-plane functions of the PDCP layer include user datatransmission, header compression, and ciphering. The control-planefunctions of the PDCP layer include control-plane data transmission andciphering/integrity protection.

RB establishment amounts to a process of defining radio protocol layersand channel features and configuring specific parameters and operationmethods in order to provide a specific service. RBs may be classifiedinto two types, signaling radio bearer (SRB) and data radio bearer(DRB). The SRB is used as a path in which an RRC message is transmittedon the control plane, whereas the DRB is used as a path in which userdata is transmitted on the user plane.

Once an RRC connection is established between the RRC layer of the UEand the RRC layer of the E-UTRAN, the UE is placed in RRC_CONNECTEDstate, and otherwise, the UE is placed in RRC_IDLE state. In NR,RRC_INACTIVE state is additionally defined. A UE in the RRC_INACTIVEstate may maintain a connection to a core network, while releasing aconnection from an eNB.

DL transport channels carrying data from the network to the UE include abroadcast channel (BCH) on which system information is transmitted and aDL shared channel (DL SCH) on which user traffic or a control message istransmitted. Traffic or a control message of a DL multicast or broadcastservice may be transmitted on the DL-SCH or a DL multicast channel (DLMCH). UL transport channels carrying data from the UE to the networkinclude a random access channel (RACH) on which an initial controlmessage is transmitted and an UL shared channel (UL SCH) on which usertraffic or a control message is transmitted.

The logical channels which are above and mapped to the transportchannels include a broadcast control channel (BCCH), a paging controlchannel (PCCH), a common control channel (CCCH), a multicast controlchannel (MCCH), and a multicast traffic channel (MTCH).

A physical channel includes a plurality of OFDM symbol in the timedomain by a plurality of subcarriers in the frequency domain. Onesubframe includes a plurality of OFDM symbols in the time domain. An RBis a resource allocation unit defined by a plurality of OFDM symbols bya plurality of subcarriers. Further, each subframe may use specificsubcarriers of specific OFDM symbols (e.g., the first OFDM symbol) in acorresponding subframe for a physical DL control channel (PDCCH), thatis, an L1/L2 control channel. A transmission time interval (TTI) is aunit time for subframe transmission.

FIG. 4 illustrates the structure of an NR system according to anembodiment of the present disclosure.

Referring to FIG. 4, a next generation radio access network (NG-RAN) mayinclude a next generation Node B (gNB) and/or an eNB, which providesuser-plane and control-plane protocol termination to a UE. In FIG. 4,the NG-RAN is shown as including only gNBs, by way of example. A gNB andan eNB are connected to each other via an Xn interface. The gNB and theeNB are connected to a 5G core network (5GC) via an NG interface. Morespecifically, the gNB and the eNB are connected to an access andmobility management function (AMF) via an NG-C interface and to a userplane function (UPF) via an NG-U interface.

FIG. 5 illustrates functional split between the NG-RAN and the 5GCaccording to an embodiment of the present disclosure.

Referring to FIG. 5, a gNB may provide functions including inter-cellradio resource management (RRM), radio admission control, measurementconfiguration and provision, and dynamic resource allocation. The AMFmay provide functions such as non-access stratum (NAS) security andidle-state mobility processing. The UPF may provide functions includingmobility anchoring and protocol data unit (PDU) processing. A sessionmanagement function (SMF) may provide functions including UE Internetprotocol (IP) address allocation and PDU session control.

FIG. 6 illustrates a radio frame structure in NR, to which embodiment(s)of the present disclosure is applicable.

Referring to FIG. 6, a radio frame may be used for UL transmission andDL transmission in NR. A radio frame is 10 ms in length, and may bedefined by two 5-ms half-frames. An HF may include five 1-ms subframes.A subframe may be divided into one or more slots, and the number ofslots in an SF may be determined according to a subcarrier spacing(SCS). Each slot may include 12 or 14 OFDM(A) symbols according to acyclic prefix (CP).

In a normal CP (NCP) case, each slot may include 14 symbols, whereas inan extended CP (ECP) case, each slot may include 12 symbols. Herein, asymbol may be an OFDM symbol (or CP-OFDM symbol) or an SC-FDMA symbol(or DFT-s-OFDM symbol).

[Table 1] below lists the number of symbols per slot N^(slot) _(symb),the number of slots per frame N^(frame,u) _(slot), and the number ofslots per subframe N^(subframe,u) _(slot) according to an SCSconfiguration μ in the NCP case.

TABLE 1 SCS (15*2u) N^(slot) _(symb) N^(frame, u) _(slot)N^(subframe, u) _(slot)  15 KHz (u = 0) 14 10 1  30 KHz (u = 1) 14 20 2 60 KHz (u = 2) 14 40 4 120 KHz (u = 3) 14 80 8 240 KHz (u = 4) 14 16016

[Table 2] below lists the number of symbols per slot, the number ofslots per frame, and the number of slots per subframe according to anSCS in the ECP case.

TABLE 2 SCS (15*2{circumflex over ( )}u) N^(slot) _(symb) N^(frame, u)_(slot) N^(subframe, u) _(slot) 60 KHz (u = 2) 12 40 4

In the NR system, different OFDM(A) numerologies (e.g., SCSs, CPlengths, and so on) may be configured for a plurality of cellsaggregated for one UE. Accordingly, the (absolute time) duration of atime resource including the same number of symbols (e.g., a subframe,slot, or TTI) (collectively referred to as a time unit (TU) forconvenience) may be configured to be different for the aggregated cells.

In NR, various numerologies or SCSs may be supported to support various5G services. For example, with an SCS of 15 kHz, a wide area intraditional cellular bands may be supported, while with an SCS of 30kHz/60 kHz, a dense urban area, a lower latency, and a wide carrierbandwidth may be supported. With an SCS of 60 kHz or higher, a bandwidthlarger than 24.25 GHz may be supported to overcome phase noise.

An NR frequency band may be defined by two types of frequency ranges,FR1 and FR2. The numerals in each frequency range may be changed. Forexample, the two types of frequency ranges may be given in [Table 3]. Inthe NR system, FR1 may be a “sub 6 GHz range” and FR2 may be an “above 6GHz range” called millimeter wave (mmW).

TABLE 3 Frequency Range Corresponding designation frequency rangeSubcarrier Spacing (SCS) FR1  450 MHz-6000 MHz  15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

As mentioned above, the numerals in a frequency range may be changed inthe NR system. For example, FR1 may range from 410 MHz to 7125 MHz aslisted in [Table 4]. That is, FR1 may include a frequency band of 6 GHz(or 5850, 5900, and 5925 MHz) or above. For example, the frequency bandof 6 GHz (or 5850, 5900, and 5925 MHz) or above may include anunlicensed band. The unlicensed band may be used for various purposes,for example, vehicle communication (e.g., autonomous driving).

TABLE 4 Frequency Range Corresponding designation frequency rangeSubcarrier Spacing (SCS) FR1  410 MHz-7125 MHz  15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

FIG. 7 illustrates a slot structure in an NR frame according to anembodiment of the present disclosure.

Referring to FIG. 7, a slot includes a plurality of symbols in the timedomain. For example, one slot may include 14 symbols in an NCP case and12 symbols in an ECP case. Alternatively, one slot may include 7 symbolsin an NCP case and 6 symbols in an ECP case.

A carrier includes a plurality of subcarriers in the frequency domain.An RB may be defined by a plurality of (e.g., 12) consecutivesubcarriers in the frequency domain. A bandwidth part (BWP) may bedefined by a plurality of consecutive (physical) RBs ((P)RBs) in thefrequency domain and correspond to one numerology (e.g., SCS, CP length,or the like). A carrier may include up to N (e.g., 5) BWPs. Datacommunication may be conducted in an activated BWP. Each element may bereferred to as a resource element (RE) in a resource grid, to which onecomplex symbol may be mapped.

A radio interface between UEs or a radio interface between a UE and anetwork may include L1, L2, and L3. In various embodiments of thepresent disclosure, L1 may refer to the PHY layer. For example, L2 mayrefer to at least one of the MAC layer, the RLC layer, the PDCH layer,or the SDAP layer. For example, L3 may refer to the RRC layer.

Now, a description will be given of sidelink (SL) communication.

FIG. 8 illustrates a radio protocol architecture for SL communicationaccording to an embodiment of the present disclosure. Specifically, FIG.8(a) illustrates a user-plane protocol stack in LTE, and FIG. 8(b)illustrates a control-plane protocol stack in LTE.

FIG. 9 illustrates a radio protocol architecture for SL communicationaccording to an embodiment of the present disclosure. Specifically, FIG.9(a) illustrates a user-plane protocol stack in NR, and FIG. 9(b)illustrates a control-plane protocol stack in NR.

Resource allocation in SL will be described below.

FIG. 10 illustrates a procedure of performing V2X or SL communicationaccording to a transmission mode in a UE according to an embodiment ofthe present disclosure. In various embodiments of the presentdisclosure, a transmission mode may also be referred to as a mode or aresource allocation mode. For the convenience of description, atransmission mode in LTE may be referred to as an LTE transmission mode,and a transmission mode in NR may be referred to as an NR resourceallocation mode.

For example, FIG. 10(a) illustrates a UE operation related to LTEtransmission mode 1 or LTE transmission mode 3. Alternatively, forexample, FIG. 10(a) illustrates a UE operation related to NR resourceallocation mode 1. For example, LTE transmission mode 1 may be appliedto general SL communication, and LTE transmission mode 3 may be appliedto V2X communication.

For example, FIG. 10(b) illustrates a UE operation related to LTEtransmission mode 2 or LTE transmission mode 4. Alternatively, forexample, FIG. 10(b) illustrates a UE operation related to NR resourceallocation mode 2.

Referring to FIG. 10(a), in LTE transmission mode 1, LTE transmissionmode 3, or NR resource allocation mode 1, a BS may schedule SL resourcesto be used for SL transmission of a UE. For example, the BS may performresource scheduling for UE1 through a PDCCH (more specifically, DLcontrol information (DCI)), and UE1 may perform V2X or SL communicationwith UE2 according to the resource scheduling. For example, UE1 maytransmit sidelink control information (SCI) to UE2 on a PSCCH, and thentransmit data based on the SCI to UE2 on a PSSCH.

For example, in NR resource allocation mode 1, a UE may be provided withor allocated resources for one or more SL transmissions of one transportblock (TB) by a dynamic grant from the BS. For example, the BS mayprovide the UE with resources for transmission of a PSCCH and/or a PSSCHby the dynamic grant. For example, a transmitting UE may report an SLhybrid automatic repeat request (SL HARQ) feedback received from areceiving UE to the BS. In this case, PUCCH resources and a timing forreporting the SL HARQ feedback to the BS may be determined based on anindication in a PDCCH, by which the BS allocates resources for SLtransmission.

For example, the DCI may indicate a slot offset between the DCIreception and a first SL transmission scheduled by the DCI. For example,a minimum gap between the DCI that schedules the SL transmissionresources and the resources of the first scheduled SL transmission maynot be smaller than a processing time of the UE.

For example, in NR resource allocation mode 1, the UE may beperiodically provided with or allocated a resource set for a pluralityof SL transmissions through a configured grant from the BS. For example,the grant to be configured may include configured grant type 1 orconfigured grant type 2. For example, the UE may determine a TB to betransmitted in each occasion indicated by a given configured grant.

For example, the BS may allocate SL resources to the UE in the samecarrier or different carriers.

For example, an NR gNB may control LTE-based SL communication. Forexample, the NR gNB may transmit NR DCI to the UE to schedule LTE SLresources. In this case, for example, a new RNTI may be defined toscramble the NR DCI. For example, the UE may include an NR SL module andan LTE SL module.

For example, after the UE including the NR SL module and the LTE SLmodule receives NR SL DCI from the gNB, the NR SL module may convert theNR SL DCI into LTE DCI type 5A, and transmit LTE DCI type 5A to the LTESL module every X ms. For example, after the LTE SL module receives LTEDCI format 5A from the NR SL module, the LTE SL module may activateand/or release a first LTE subframe after Z ms. For example, X may bedynamically indicated by a field of the DCI. For example, a minimumvalue of X may be different according to a UE capability. For example,the UE may report a single value according to its UE capability. Forexample, X may be positive.

Referring to FIG. 10(b), in LTE transmission mode 2, LTE transmissionmode 4, or NR resource allocation mode 2, the UE may determine SLtransmission resources from among SL resources preconfigured orconfigured by the BS/network. For example, the preconfigured orconfigured SL resources may be a resource pool. For example, the UE mayautonomously select or schedule SL transmission resources. For example,the UE may select resources in a configured resource pool on its own andperform SL communication in the selected resources. For example, the UEmay select resources within a selection window on its own by a sensingand resource (re)selection procedure. For example, the sensing may beperformed on a subchannel basis. UE1, which has autonomously selectedresources in a resource pool, may transmit SCI to UE2 on a PSCCH andthen transmit data based on the SCI to UE2 on a PSSCH.

For example, a UE may help another UE with SL resource selection. Forexample, in NR resource allocation mode 2, the UE may be configured witha grant configured for SL transmission. For example, in NR resourceallocation mode 2, the UE may schedule SL transmission for another UE.For example, in NR resource allocation mode 2, the UE may reserve SLresources for blind retransmission.

For example, in NR resource allocation mode 2, UE1 may indicate thepriority of SL transmission to UE2 by SCI. For example, UE2 may decodethe SCI and perform sensing and/or resource (re)selection based on thepriority. For example, the resource (re)selection procedure may includeidentifying candidate resources in a resource selection window by UE2and selecting resources for (re)transmission from among the identifiedcandidate resources by UE2. For example, the resource selection windowmay be a time interval during which the UE selects resources for SLtransmission. For example, after UE2 triggers resource (re)selection,the resource selection window may start at T1≥0, and may be limited bythe remaining packet delay budget of UE2. For example, when specificresources are indicated by the SCI received from UE1 by the second UEand an L1 SL reference signal received power (RSRP) measurement of thespecific resources exceeds an SL RSRP threshold in the step ofidentifying candidate resources in the resource selection window by UE2,UE2 may not determine the specific resources as candidate resources. Forexample, the SL RSRP threshold may be determined based on the priorityof SL transmission indicated by the SCI received from UE1 by UE2 and thepriority of SL transmission in the resources selected by UE2.

For example, the L1 SL RSRP may be measured based on an SL demodulationreference signal (DMRS). For example, one or more PSSCH DMRS patternsmay be configured or preconfigured in the time domain for each resourcepool. For example, PDSCH DMRS configuration type 1 and/or type 2 may beidentical or similar to a PSSCH DMRS pattern in the frequency domain.For example, an accurate DMRS pattern may be indicated by the SCI. Forexample, in NR resource allocation mode 2, the transmitting UE mayselect a specific DMRS pattern from among DMRS patterns configured orpreconfigured for the resource pool.

For example, in NR resource allocation mode 2, the transmitting UE mayperform initial transmission of a TB without reservation based on thesensing and resource (re)selection procedure. For example, thetransmitting UE may reserve SL resources for initial transmission of asecond TB using SCI associated with a first TB based on the sensing andresource (re)selection procedure.

For example, in NR resource allocation mode 2, the UE may reserveresources for feedback-based PSSCH retransmission through signalingrelated to a previous transmission of the same TB. For example, themaximum number of SL resources reserved for one transmission, includinga current transmission, may be 2, 3 or 4. For example, the maximumnumber of SL resources may be the same regardless of whether HARQfeedback is enabled. For example, the maximum number of HARQ(re)transmissions for one TB may be limited by a configuration orpreconfiguration. For example, the maximum number of HARQ(re)transmissions may be up to 32. For example, if there is noconfiguration or preconfiguration, the maximum number of HARQ(re)transmissions may not be specified. For example, the configurationor preconfiguration may be for the transmitting UE. For example, in NRresource allocation mode 2, HARQ feedback for releasing resources whichare not used by the UE may be supported.

For example, in NR resource allocation mode 2, the UE may indicate oneor more subchannels and/or slots used by the UE to another UE by SCI.For example, the UE may indicate one or more subchannels and/or slotsreserved for PSSCH (re)transmission by the UE to another UE by SCI. Forexample, a minimum allocation unit of SL resources may be a slot. Forexample, the size of a subchannel may be configured or preconfigured forthe UE.

SCI will be described below.

While control information transmitted from a BS to a UE on a PDCCH isreferred to as DCI, control information transmitted from one UE toanother UE on a PSCCH may be referred to as SCI. For example, the UE mayknow the starting symbol of the PSCCH and/or the number of symbols inthe PSCCH before decoding the PSCCH. For example, the SCI may include SLscheduling information. For example, the UE may transmit at least oneSCI to another UE to schedule the PSSCH. For example, one or more SCIformats may be defined.

For example, the transmitting UE may transmit the SCI to the receivingUE on the PSCCH. The receiving UE may decode one SCI to receive thePSSCH from the transmitting UE.

For example, the transmitting UE may transmit two consecutive SCIs(e.g., 2-stage SCI) on the PSCCH and/or PSSCH to the receiving UE. Thereceiving UE may decode the two consecutive SCIs (e.g., 2-stage SCI) toreceive the PSSCH from the transmitting UE. For example, when SCIconfiguration fields are divided into two groups in consideration of a(relatively) large SCI payload size, SCI including a first SCIconfiguration field group is referred to as first SCI. SCI including asecond SCI configuration field group may be referred to as second SCI.For example, the transmitting UE may transmit the first SCI to thereceiving UE on the PSCCH. For example, the transmitting UE may transmitthe second SCI to the receiving UE on the PSCCH and/or PSSCH. Forexample, the second SCI may be transmitted to the receiving UE on an(independent) PSCCH or on a PSSCH in which the second SCI is piggybackedto data. For example, the two consecutive SCIs may be applied todifferent transmissions (e.g., unicast, broadcast, or groupcast).

For example, the transmitting UE may transmit all or part of thefollowing information to the receiving UE by SCI. For example, thetransmitting UE may transmit all or part of the following information tothe receiving UE by first SCI and/or second SCI.

-   -   PSSCH-related and/or PSCCH-related resource allocation        information, for example, the positions/number of time/frequency        resources, resource reservation information (e.g. a        periodicity), and/or    -   an SL channel state information (CSI) report request indicator        or SL (L1) RSRP (and/or SL (L1) reference signal received        quality (RSRQ) and/or SL (L1) received signal strength indicator        (RSSI)) report request indicator, and/or    -   an SL CSI transmission indicator (on PSSCH) (or SL (L1) RSRP        (and/or SL (L1) RSRQ and/or SL (L1) RSSI) information        transmission indicator), and/or    -   MCS information, and/or    -   transmission power information, and/or    -   L1 destination ID information and/or L1 source ID information,        and/or    -   SL HARQ process ID information, and/or    -   new data indicator (NDI) information, and/or    -   redundancy version (RV) information, and/or    -   QoS information (related to transmission traffic/packet), for        example, priority information, and/or    -   an SL CSI-RS transmission indicator or information about the        number of SL CSI-RS antenna ports (to be transmitted);    -   location information about a transmitting UE or location (or        distance area) information about a target receiving UE        (requested to transmit an SL HARQ feedback), and/or    -   RS (e.g., DMRS or the like) information related to decoding        and/or channel estimation of data transmitted on a PSSCH, for        example, information related to a pattern of (time-frequency)        mapping resources of the DMRS, rank information, and antenna        port index information.

For example, the first SCI may include information related to channelsensing. For example, the receiving UE may decode the second SCI usingthe PSSCH DMRS. A polar code used for the PDCCH may be applied to thesecond SCI. For example, the payload size of the first SCI may be equalfor unicast, groupcast and broadcast in a resource pool. After decodingthe first SCI, the receiving UE does not need to perform blind decodingon the second SCI. For example, the first SCI may include schedulinginformation about the second SCI.

In various embodiments of the present disclosure, since the transmittingUE may transmit at least one of the SCI, the first SCI, or the secondSCI to the receiving UE on the PSCCH, the PSCCH may be replaced with atleast one of the SCI, the first SCI, or the second SC. Additionally oralternatively, for example, the SCI may be replaced with at least one ofthe PSCCH, the first SCI, or the second SCI. Additionally oralternatively, for example, since the transmitting UE may transmit thesecond SCI to the receiving UE on the PSSCH, the PSSCH may be replacedwith the second SCI.

A buffer status reporting or (buffer status report) (BSR) procedure maybe used to provide information about the UL data volume of a MAC entityto a serving gNB.

In the case of IAB, it is additionally used by an IAB-MT to provide itsparent IAB-DU with the information about the amount of the data expectedto arrive at the MT of the IAB node from its child node(s) and or UE(s)connected to it. This BSR is referred to as Pre-emptive BSR.

In the case of integrated access and backhaul (IAB), information on theamount of data expected to arrive at the mobile termination (MT) of anIAB node from lower node(s) or UE(s) connected to an upper IABdistributed unit (IAB-DU) may be provided. This BSR is calledpre-emptive BSR.

For BSR other than pre-emptive BSR, the following parameters areconfigured by RRC to control the BSR.

-   -   periodicB SR-Timer;    -   retxBSR-Timer;    -   logicalChannelSR-DelayTimerApplied;    -   logicalChannelSR-DelayTimer;    -   logicalChannelSR-Mask;    -   logicalChannelGroup.

Each logical channel may be allocated to a logical channel group (LCG)by logicalChannelGroup. The maximum number of LCGs is 8.

The MAC entity determines the amount of UL data available for a logicalchannel according to the data volume calculation procedure in TS 38.322and TS 38.323.

BSR other than pre-emptive BSR shall be triggered if any of thefollowing events occur.

-   -   UL data for a logical channel that belongs to an LCG becomes        available to the MAC entity. (This UL data belongs to a logical        channel with higher priority than the priority of any logical        channel including available UL data that belongs to any LCG, or        there is no available UL data in logical channels belong to an        LCG. Thus, such BSR is referred to as ‘regular BSR’).    -   When UL resources are allocated and when the number of padding        bits is more than or equal to the size of a BSR MAC CE and a        subheader thereof, such BSR is referred to as ‘padding BSR’.    -   When retxBSR-Timer expires and when at least one of the logical        channels that belong to an LCG contains UL data, such BSR is        referred to as ‘regular BSR’.    -   When periodicBSR-Timer expires, such BSR is referred to as        ‘periodic BSR’.

The MAC entity may need to restart retxB SR-Timer upon receiving a grantfor transmission of new data on a UL-SCH.

All triggered BSR other than pre-emptive BSR may be cancelled if a ULgrant is capable of accommodating all pending data available fortransmission but is not sufficient to additionally accommodate a BSR MACCE and a subheader thereof. All BSR other than pre-emptive BSR triggeredbefore assembly of a MAC PDU may be cancelled when the MAC PDU istransmitted, regardless of LBT failure indication from lower layers. Inthis case, the PDU includes a long or short BSR MAC CE including amaximum buffer status.

The MAC entity may be configured by RRC per serving cell with a beamfailure recovery (BFR) procedure which is used to indicate to a servinggNB of a new SSB or CSI-RS when beam failure is detected onSSB(s)/CSI-RS(s). Beam failure is detected by counting the number ofbeam failure instance indications from lower layers to the MAC entity.The BFR procedure may be performed according to Table 5, which isextracted from 3GPP TS 38.321.

TABLE 5 The MAC entity shall for each Serving Cell configured for beamfailure detection:  1> if beam failure instance indication has beenreceived from lower layers:   2> start or restart thebeamFailureDetectionTimer,   2> increment BFI_COUNTER by 1;   2> ifBFI_COUNTER >= beamFailureInstanceMaxCount:    3> if the Serving Cell isSCell:     4> trigger a BFR for this Serving Cell;    3> else:     4>initiate a Random Access procedure (see clause 5.1) on the SpCell.  1>if the beamFailureDetectionTimer expires; or  1> ifbeamFailureDetectionTimer, beamFailureInstanceMaxCount, or any of thereference signals used for beam    failure detection is reconfigured byupper layers associated with this Serving Cell:   2> set BFI_COUNTER to0.  1> if the Serving Cell is SpCell and the Random Access procedureinitiated for SpCell beam failure recovery is    successfully completed(see clause 5.1):   2> set BFI_COUNTER to 0;   2> stop thebeamFailureRecoveryTimer, if configured;   2> consider the Beam FailureRecovery procedure successfully completed.  1> else if the Serving Cellis SCell, and a PDCCH addressed to C-RNTI indicating uplink grant for anew    transmission is received for the HARQ process used for thetransmission of the BFR MAC CE or Truncated    BFR MAC CE which containsbeam failure recovery information of this Serving Cell; or  1> if theSCell is deactivated as specified in clause 5.9:   2> set BFI_COUNTER to0;   2> consider the Beam Failure Recovery procedure successfullycompleted and cancel all the triggered BFRs for     this Serving Cell.The MAC entity shall:  1> if the Beam Failure Recovery proceduredetermines that at least one BFR has been triggered and not cancelled:  2> if UL-SCH resources are available for a new transmission and if theUL-SCH resources can accommodate     the BFR MAC CE plus its subheaderas a result of LCP:    3> instruct the Multiplexing and Assemblyprocedure to generate the BFR MAC CE.   2> else if UL-SCH resources areavailable for a new transmission and if the UL-SCH resources can    accommodate the Truncated BFR MAC CE plus its subheader as a resultof LCP:    3> instruct the Multiplexing and Assembly procedure togenerate the Truncated BFR MAC CE.   2> else:    3> trigger the SR forSCell beam failure recovery for each SCell for which BFR has beentriggered and not      cancelled. All BFRs triggered prior to MAC PDUassembly for beam failure recovery for an SCell shall be cancelled whena MAC PDU is transmitted and this PDU includes a BFR MAC CE or TruncatedBFR MAC CE which contains beam failure information of that SCell.

According to current NR Uu, if the UE starts the BFR procedure bydetecting beam failure a maximum number of times, triggered BSR for ULdata transmission to the BS may pend until the beam failure isrecovered. In the NR Uu operation, no SR/BSR procedures have beendefined for the occurrence of beam failure. Therefore, in a NR Uu normalBSR procedure, if regular BSR is triggered, the triggered BSR isconsidered as pending BSR until the triggered BSR is processed. Whenthis operation is applied to beam failure situations, a procedure ofconsidering BSR triggered by the start of BFR as pending BSR may beregarded as a conventional one. When beam failure on a Uu link isrecovered, the UE may be allocated UL resources from the BS by processpending BSR. In addition, if a problem occurs in a selected beam while aV2X device maintains a connection with the BS on the selected beam(e.g., if beam failure occurs), it may affect sidelink communicationbetween V2X devices.

When a V2X UE is allocated resources from the BS according to a Mode 1method (e.g., Mode 1 dynamic scheduling) and performs sidelinkcommunication, if beam failure occurs for a beam selected by the UE on aUu link, the UE may perform the BFR procedure. As a result, there may bea problem that the UE is incapable of normally performing a “Mode 1resource allocation request (SR/BSR) procedure” for sidelinkcommunication to the BS while performing the corresponding BFR procedure(that is, due to failure in the currently used beam, the UE may not senda sidelink resource request to the BS until the UE selects a new beambased on the BFR procedure). In the above situation, the UE may switchto a mode for using Mode 2 resources to temporarily use the Mode 2resources (TX exception pool) during the BFR procedure and then performsidelink communication. In the current specifications, it has not beendefined whether a V2X TX UE defers triggered BSR during BFR and resumesthe pending BSR after beam recovery or cancels the triggered BSR duringthe BFR and triggers new BSR after the beam recovery.

In the following embodiment(s), it will be described how a V2X TX UEsends a resource allocation request to a BS to receive resources fortransmitting sidelink data to an RX UE upon detecting beam failure on aUu link.

According to an embodiment of the present disclosure, a TX UE may send asidelink resource request to a BS on a first beam (S1101 in FIG. 11).The TX UE may be a Mode 1 UE and be allocated Mode 1 resources from theBS. Thereafter, the TX UE may trigger first BSR (S1102 in FIG. 11). Thefirst BSR may be based on generation of first sidelink data to betransmitted by the TX UE to an RX UE. That is, when the TX UE has datato transmit to the RX UE, the TX UE may trigger the BSR.

The TX UE may cancel the first BSR based on triggering of BFR related tothe first beam. That is, the TX UE may cancel the triggered BSR forsidelink data transmission. The first BSR may have occurred before thetriggering of the BFR.

Thereafter, the TX UE may trigger second BSR for the first sidelink datarelated to the first BSR based on selection of a second beam by the BFR.When a BFR procedure between the TX UE and BS is completed, that is,when a new beam is selected between the TX UE and BS by beam recovery,the TX UE may trigger a new BSR for the sidelink data that the Tx UE hasnot transmitted. The TX UE may transmit the second BSR to the BS on thesecond beam. That is, the TX UE may receive a grant for sidelink datatransmission from the BS by transmitting the new BSR to the BS on a beamnewly selected by the BFR.

According to the above-described configuration, it is possible toefficiently process current BSR at the occurrence of BFR. Specifically,in sidelink communication, particularly, V2X communication, the UE maymove at a high speed, and in this case, the cell may change during BFR.If the cell changes due to the (fast) movement of the UE, transmissionof the current BSR to the changed cell may be considered as unnecessarysignal transmission. Accordingly, BSR generated before triggering of BFRmay be cancelled, and new BSR may be transmitted for data of thecancelled BSR on a beam selected by the BFR, thereby achieving efficientoperation of the BSR and BFR.

In addition, according to the proposed method, UE operations may besimplified by preventing the V2X TX UE from deferring BSR until beamfailure on a Uu link is recovered. For example, when the V2X TX UEdefers the BSR due to the beam failure on the Uu link, if new sidelinkdata occurs during or after beam recovery, the TX UE needs to resume thepreviously pending BSR and also trigger new BSR for transmitting the newsidelink data after the beam failure on the Uu link is recovered.However, according to the method proposed in the embodiment(s), when theV2X TX UE cancels BSR triggered for sidelink data transmission due tobeam failure on a Uu link, even if new sidelink data occurs during orafter beam recovery, the TX UE may trigger only single BSR byaggregating new BSR information for transmitting the new sidelink dataand previously canceled BSR information together when triggering thepreviously cancelled BSR after the beam failure on the Uu link isrecovered. That is, the Mode 1 resource allocation request (SR/BSR)procedure of the TX UE may be further simplified.

If second sidelink data, which is different from the first sidelink datarelated to the first BSR, occurs after the triggering of the BFR, the TXUE may trigger third BSR, which is obtained by aggregating BSRinformation for the first sidelink data and BSR information for thesecond sidelink data. If new sidelink data occurs during or after thebeam recovery, the TX UE may trigger new BSR by aggregating BSRinformation for the sidelink data that has not previously beentransmitted and BSR information for the new sidelink data.

The first sidelink data and the second sidelink data may be related tothe same destination ID. Alternatively, the first sidelink data and thesecond sidelink data may be related to different destination IDs.

In summary, when the BFR procedure operates for a beam which is selectedand used by a Mode 1 UE and a BS on a Uu link (that is, when beamfailure occurs for the beam), if a TX UE has data to transmit to a RXUE, the TX UE may cancel BSR triggered for sidelink data transmission,instead of deferring the BSR until the beam failure is recovered. Inaddition, if a new beam is selected after the beam failure is recovered,the TX UE may trigger new BSR for the sidelink data that the TX UE hasnot transmitted. If new sidelink data occurs while the beam failure isrecovered, the TX UE may transmit new BSR by aggregating the BSR for thesidelink data that has not been transmitted and BSR for transmitting thenew sidelink.

FIG. 12 illustrates a procedure related to the above-describedembodiment. Referring to FIG. 12, in step S120, a TX UE may send arequest for a Mode 1 sidelink transmission resource to a BS on aselected beam and receive the Mode 1 resource. In step S1202, if the TXUE has data to transmit to an RX UE, the TX UE may trigger BSR.

In step S1203, if the TX UE detects beam failure on a Uu link (betweenthe UE and BS) a maximum number of times, the TX UE may trigger BFR andstart a BFR timer at the same time.

In step S1204, the TX UE may cancel the triggered BSR for sidelink datatransmission.

In step S1205, the BFR procedure between the TX UE and BS may becompleted. That is, a new beam is selected between the TX UE and BS bybeam recovery. In step S1206, the TX UE may trigger new BSR for thesidelink data that the TX UE has not transmitted.

In step S1207, the TX UE may receive a grant for sidelink datatransmission from the BS by transmitting the new BSR to the BS on a beamnewly selected by the BFR.

FIG. 13 illustrates a procedure related to the above-describedembodiment. Referring to FIG. 13, in step S1301, a TX UE may send arequest for a Mode 1 sidelink transmission resource to a BS on aselected beam and receive the Mode 1 resource.

In step S1302, if the TX UE has data to transmit to an RX UE, the TX UEmay trigger BSR.

In step S1303, if the TX UE detects beam failure on a Uu link (betweenthe UE and BS) a maximum number of times, the TX UE may trigger BFR andstart a BFR timer at the same time.

In step S1304, the TX UE may cancel the triggered BSR for sidelink datatransmission.

In step S1305, the BFR procedure between the TX UE and BS may becompleted. That is, a new beam is selected between the TX UE and BS bybeam recovery.

In step S1306, when the TX UE triggers new BSR for transmitting thesidelink data that the TX UE has not transmitted, if new sidelink dataoccurs during or after the beam recovery, the TX UE may trigger new BSRby aggregating BSR information for the sidelink data that the TX UE hasnot transmitted and BSR information for the new sidelink data. As anexample, the TX UE may trigger new BSR by aggregating BSR informationfor multiple sidelink data to be transmitted to the same destination ID(the new sidelink data and the sidelink data that the TX UE has nottransmitted may be transmitted to the same RX UE (same destination ID)).As another example, even if the new sidelink data is sidelink data to betransmitted to an RX UE with a different destination ID, the TX UE maytrigger new BSR by aggregating BSR information for the multiple sidelinkdata (the new sidelink data and the sidelink data that the TX UE has nottransmitted may be transmitted to different RX UEs (differentdestination IDs)).

In step S1307, the TX UE may receive a grant for sidelink datatransmission from the BS by transmitting the new BSR to the BS on a beamnewly selected by the BFR.

According to the embodiment(s), when the V2X TX UE detects beam failureon a Uu link with the BS, the V2X TX UE may cancel previously triggeredBSR for sidelink data transmission. After the beam failure on the Uulink is recovered, the V2X TX UE may trigger new BSR and receive fromthe BS a Mode 1 resource for the sidelink data that the V2X TX UE hasnot transmitted.

Although the present disclosure has been mainly described based on beamfailure and BFR, the technical features may also be applied to Uuphysical layer problems (when physical layers continuously report out ofsync events to RRC due to a poor channel status of the Uu link or whenphysical layers continuously report out of sync events to higher layers(MAC or RRC) due to a poor channel status of the Uu link). For example,when a TX UE performing sidelink communication detects a Uu physicallayer problem, the TX UE may start a recovery timer for the physicallayer problem. In this case, triggered BSR may be canceled. After the Uuphysical layer problem, the TX UE may trigger new BSR for the canceledBSR and transmit the new BSR to a BS. As another example, whentriggering the new BSR after the physical layer problem, the TX UE maytrigger BSR by aggregating the canceled BSR and the new BSR and transmitthe BSR to the BS. The TX UE may be a Mode 1 UE. That is, the TX UE maybe allocated a Mode 1 resource from the BS.

Examples of communication systems applicable to the present disclosure

The various descriptions, functions, procedures, proposals, methods,and/or operational flowcharts of the present disclosure described inthis document may be applied to, without being limited to, a variety offields requiring wireless communication/connection (e.g., 5G) betweendevices.

Hereinafter, a description will be given in more detail with referenceto the drawings. In the following drawings/description, the samereference symbols may denote the same or corresponding hardware blocks,software blocks, or functional blocks unless described otherwise.

FIG. 14 illustrates a communication system 1 applied to the presentdisclosure.

Referring to FIG. 14, a communication system 1 applied to the presentdisclosure includes wireless devices, BSs, and a network. Herein, thewireless devices represent devices performing communication using RAT(e.g., 5G NR or LTE) and may be referred to as communication/radio/5Gdevices. The wireless devices may include, without being limited to, arobot 100 a, vehicles 100 b-1 and 100 b-2, an extended reality (XR)device 100 c, a hand-held device 100 d, a home appliance 100 e, anInternet of things (IoT) device 100 f, and an artificial intelligence(AI) device/server 400. For example, the vehicles may include a vehiclehaving a wireless communication function, an autonomous driving vehicle,and a vehicle capable of performing communication between vehicles.Herein, the vehicles may include an unmanned aerial vehicle (UAV) (e.g.,a drone). The XR device may include an augmented reality (AR)/virtualreality (VR)/mixed reality (MR) device and may be implemented in theform of a head-mounted device (HMD), a head-up display (HUD) mounted ina vehicle, a television, a smartphone, a computer, a wearable device, ahome appliance device, a digital signage, a vehicle, a robot, etc. Thehand-held device may include a smartphone, a smartpad, a wearable device(e.g., a smartwatch or a smartglasses), and a computer (e.g., anotebook). The home appliance may include a TV, a refrigerator, and awashing machine. The IoT device may include a sensor and a smartmeter.For example, the BSs and the network may be implemented as wirelessdevices and a specific wireless device 200 a may operate as a BS/networknode with respect to other wireless devices.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g.,NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300, thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without passing through theBSs/network. For example, the vehicles 100 b-1 and 100 b-2 may performdirect communication (e.g. V2V/V2X communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b, or 150 c may beestablished between the wireless devices 100 a to 100 f/BS 200, or BS200/BS 200. Herein, the wireless communication/connections may beestablished through various RATs (e.g., 5G NR) such as UL/DLcommunication 150 a, sidelink communication 150 b (or, D2Dcommunication), or inter BS communication (e.g. relay, integrated accessbackhaul (IAB)). The wireless devices and the BSs/the wireless devicesmay transmit/receive radio signals to/from each other through thewireless communication/connections 150 a and 150 b. For example, thewireless communication/connections 150 a and 150 b may transmit/receivesignals through various physical channels. To this end, at least a partof various configuration information configuring processes, varioussignal processing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocating processes, for transmitting/receiving radio signals, may beperformed based on the various proposals of the present disclosure.

Examples of wireless devices applicable to the present disclosure

FIG. 15 illustrates wireless devices applicable to the presentdisclosure.

Referring to FIG. 15, a first wireless device 100 and a second wirelessdevice 200 may transmit radio signals through a variety of RATs (e.g.,LTE and NR). Herein, {the first wireless device 100 and the secondwireless device 200} may correspond to {the wireless device 100 x andthe BS 200} and/or {the wireless device 100 x and the wireless device100 x} of FIG. 14.

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 102 may process informationwithin the memory(s) 104 to generate first information/signals and thentransmit radio signals including the first information/signals throughthe transceiver(s) 106. The processor(s) 102 may receive radio signalsincluding second information/signals through the transceiver 106 andthen store information obtained by processing the secondinformation/signals in the memory(s) 104. The memory(s) 104 may beconnected to the processor(s) 102 and may store a variety of informationrelated to operations of the processor(s) 102. For example, thememory(s) 104 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 102or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 102 and the memory(s) 104 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 106 may be connected to the processor(s) 102 andtransmit and/or receive radio signals through one or more antennas 108.Each of the transceiver(s) 106 may include a transmitter and/or areceiver. The transceiver(s) 106 may be interchangeably used with RadioFrequency (RF) unit(s). In the present disclosure, the wireless devicemay represent a communication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 202 may process informationwithin the memory(s) 204 to generate third information/signals and thentransmit radio signals including the third information/signals throughthe transceiver(s) 206. The processor(s) 202 may receive radio signalsincluding fourth information/signals through the transceiver(s) 106 andthen store information obtained by processing the fourthinformation/signals in the memory(s) 204. The memory(s) 204 may beconnected to the processor(s) 202 and may store a variety of informationrelated to operations of the processor(s) 202. For example, thememory(s) 204 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 202or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 202 and the memory(s) 204 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 206 may be connected to the processor(s) 202 andtransmit and/or receive radio signals through one or more antennas 208.Each of the transceiver(s) 206 may include a transmitter and/or areceiver. The transceiver(s) 206 may be interchangeably used with RFunit(s). In the present disclosure, the wireless device may represent acommunication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP,RRC, and SDAP). The one or more processors 102 and 202 may generate oneor more Protocol Data Units (PDUs) and/or one or more service data unit(SDUs) according to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Theone or more processors 102 and 202 may generate messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document. The one or more processors 102 and 202 maygenerate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document and provide thegenerated signals to the one or more transceivers 106 and 206. The oneor more processors 102 and 202 may receive the signals (e.g., basebandsignals) from the one or more transceivers 106 and 206 and acquire thePDUs, SDUs, messages, control information, data, or informationaccording to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreapplication specific integrated circuits (ASICs), one or more digitalsignal processors (DSPs), one or more digital signal processing devices(DSPDs), one or more programmable logic devices (PLDs), or one or morefield programmable gate arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument may be implemented using firmware or software and the firmwareor software may be configured to include the modules, procedures, orfunctions. Firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be included in the one or more processors102 and 202 or stored in the one or more memories 104 and 204 so as tobe driven by the one or more processors 102 and 202. The descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be implemented using firmware or softwarein the form of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured by read-onlymemories (ROMs), random access memories (RAMs), electrically erasableprogrammable read-only memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, from one or moreother devices. For example, the one or more transceivers 106 and 206 maybe connected to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may perform control so that the one or more transceivers 106 and 206may transmit user data, control information, or radio signals to one ormore other devices. The one or more processors 102 and 202 may performcontrol so that the one or more transceivers 106 and 206 may receiveuser data, control information, or radio signals from one or more otherdevices. The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or more transceivers106 and 206 may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, through the one ormore antennas 108 and 208. In this document, the one or more antennasmay be a plurality of physical antennas or a plurality of logicalantennas (e.g., antenna ports). The one or more transceivers 106 and 206may convert received radio signals/channels etc. from RF band signalsinto baseband signals in order to process received user data, controlinformation, radio signals/channels, etc. using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206 mayconvert the user data, control information, radio signals/channels, etc.processed using the one or more processors 102 and 202 from the baseband signals into the RF band signals. To this end, the one or moretransceivers 106 and 206 may include (analog) oscillators and/orfilters.

Examples of a vehicle or an autonomous driving vehicle applicable to thepresent disclosure

FIG. 16 illustrates a vehicle or an autonomous driving vehicle appliedto the present disclosure. The vehicle or autonomous driving vehicle maybe implemented by a mobile robot, a car, a train, a manned/unmannedaerial vehicle (AV), a ship, etc.

Referring to FIG. 16, a vehicle or autonomous driving vehicle 100 mayinclude an antenna unit 108, a communication unit 110, a control unit120, a driving unit 140 a, a power supply unit 140 b, a sensor unit 140c, and an autonomous driving unit 140 d. The antenna unit 108 may beconfigured as a part of the communication unit 110. The blocks110/130/140 a to 140 d correspond to the blocks 110/130/140 of FIG. 43,respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous driving vehicle 100. The control unit 120 mayinclude an ECU. The driving unit 140 a may cause the vehicle or theautonomous driving vehicle 100 to drive on a road. The driving unit 140a may include an engine, a motor, a powertrain, a wheel, a brake, asteering device, etc. The power supply unit 140 b may supply power tothe vehicle or the autonomous driving vehicle 100 and include awired/wireless charging circuit, a battery, etc. The sensor unit 140 cmay acquire a vehicle state, ambient environment information, userinformation, etc. The sensor unit 140 c may include an inertialmeasurement unit (IMU) sensor, a collision sensor, a wheel sensor, aspeed sensor, a slope sensor, a weight sensor, a heading sensor, aposition module, a vehicle forward/backward sensor, a battery sensor, afuel sensor, a tire sensor, a steering sensor, a temperature sensor, ahumidity sensor, an ultrasonic sensor, an illumination sensor, a pedalposition sensor, etc. The autonomous driving unit 140 d may implementtechnology for maintaining a lane on which a vehicle is driving,technology for automatically adjusting speed, such as adaptive cruisecontrol, technology for autonomously driving along a determined path,technology for driving by automatically setting a path if a destinationis set, and the like.

For example, the communication unit 110 may receive map data, trafficinformation data, etc. from an external server. The autonomous drivingunit 140 d may generate an autonomous driving path and a driving planfrom the obtained data. The control unit 120 may control the drivingunit 140 a such that the vehicle or the autonomous driving vehicle 100may move along the autonomous driving path according to the driving plan(e.g., speed/direction control). In the middle of autonomous driving,the communication unit 110 may aperiodically/periodically acquire recenttraffic information data from the external server and acquiresurrounding traffic information data from neighboring vehicles. In themiddle of autonomous driving, the sensor unit 140 c may obtain a vehiclestate and/or surrounding environment information. The autonomous drivingunit 140 d may update the autonomous driving path and the driving planbased on the newly obtained data/information. The communication unit 110may transfer information about a vehicle position, the autonomousdriving path, and/or the driving plan to the external server. Theexternal server may predict traffic information data using AItechnology, etc., based on the information collected from vehicles orautonomous driving vehicles and provide the predicted trafficinformation data to the vehicles or the autonomous driving vehicles.

Examples of a vehicle and AR/VR applicable to the present disclosure

FIG. 17 illustrates a vehicle applied to the present disclosure. Thevehicle may be implemented as a transport means, an aerial vehicle, aship, etc.

Referring to FIG. 17, a vehicle 100 may include a communication unit110, a control unit 120, a memory unit 130, an I/O unit 140 a, and apositioning unit 140 b. Herein, the blocks 110 to 130/140 a and 140 bcorrespond to blocks 110 to 130/140 of FIG. 43.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as other vehiclesor BSs. The control unit 120 may perform various operations bycontrolling constituent elements of the vehicle 100. The memory unit 130may store data/parameters/programs/code/commands for supporting variousfunctions of the vehicle 100. The I/O unit 140 a may output an AR/VRobject based on information within the memory unit 130. The I/O unit 140a may include an HUD. The positioning unit 140 b may acquire informationabout the position of the vehicle 100. The position information mayinclude information about an absolute position of the vehicle 100,information about the position of the vehicle 100 within a travelinglane, acceleration information, and information about the position ofthe vehicle 100 from a neighboring vehicle. The positioning unit 140 bmay include a GPS and various sensors.

As an example, the communication unit 110 of the vehicle 100 may receivemap information and traffic information from an external server andstore the received information in the memory unit 130. The positioningunit 140 b may obtain the vehicle position information through the GPSand various sensors and store the obtained information in the memoryunit 130. The control unit 120 may generate a virtual object based onthe map information, traffic information, and vehicle positioninformation and the I/O unit 140 a may display the generated virtualobject in a window in the vehicle (1410 and 1420). The control unit 120may determine whether the vehicle 100 normally drives within a travelinglane, based on the vehicle position information. If the vehicle 100abnormally exits from the traveling lane, the control unit 120 maydisplay a warning on the window in the vehicle through the I/O unit 140a. In addition, the control unit 120 may broadcast a warning messageregarding driving abnormity to neighboring vehicles through thecommunication unit 110. According to situation, the control unit 120 maytransmit the vehicle position information and the information aboutdriving/vehicle abnormality to related organizations.

Examples of an XR device applicable to the present disclosure

FIG. 18 illustrates an XR device applied to the present disclosure. TheXR device may be implemented by an HMD, an HUD mounted in a vehicle, atelevision, a smartphone, a computer, a wearable device, a homeappliance, a digital signage, a vehicle, a robot, etc.

Referring to FIG. 18, an XR device 100 a may include a communicationunit 110, a control unit 120, a memory unit 130, an I/O unit 140 a, asensor unit 140 b, and a power supply unit 140 c. Herein, the blocks 110to 130/140 a to 140 c correspond to the blocks 110 to 130/140 of FIG.43, respectively.

The communication unit 110 may transmit and receive signals (e.g., mediadata and control signals) to and from external devices such as otherwireless devices, hand-held devices, or media servers. The media datamay include video, images, and sound. The control unit 120 may performvarious operations by controlling constituent elements of the XR device100 a. For example, the control unit 120 may be configured to controland/or perform procedures such as video/image acquisition, (video/image)encoding, and metadata generation and processing. The memory unit 130may store data/parameters/programs/code/commands needed to drive the XRdevice 100 a/generate XR object. The I/O unit 140 a may obtain controlinformation and data from the exterior and output the generated XRobject. The I/O unit 140 a may include a camera, a microphone, a userinput unit, a display unit, a speaker, and/or a haptic module. Thesensor unit 140 b may obtain an XR device state, surrounding environmentinformation, user information, etc. The sensor unit 140 b may include aproximity sensor, an illumination sensor, an acceleration sensor, amagnetic sensor, a gyro sensor, an inertial sensor, an RGB sensor, an IRsensor, a fingerprint recognition sensor, an ultrasonic sensor, a lightsensor, a microphone and/or a radar. The power supply unit 140 c maysupply power to the XR device 100 a and include a wired/wirelesscharging circuit, a battery, etc.

For example, the memory unit 130 of the XR device 100 a may includeinformation (e.g., data) needed to generate the XR object (e.g., anAR/VR/MR object). The I/O unit 140 a may receive a command formanipulating the XR device 100 a from a user and the control unit 120may drive the XR device 100 a according to a driving command of a user.For example, when a user desires to watch a film or news through the XRdevice 100 a, the control unit 120 transmits content request informationto another device (e.g., a hand-held device 100 b) or a media serverthrough the communication unit 130. The communication unit 130 maydownload/stream content such as films or news from another device (e.g.,the hand-held device 100 b) or the media server to the memory unit 130.The control unit 120 may control and/or perform procedures such asvideo/image acquisition, (video/image) encoding, and metadatageneration/processing with respect to the content and generate/outputthe XR object based on information about a surrounding space or a realobject obtained through the I/O unit 140 a/sensor unit 140 b.

The XR device 100 a may be wirelessly connected to the hand-held device100 b through the communication unit 110 and the operation of the XRdevice 100 a may be controlled by the hand-held device 100 b. Forexample, the hand-held device 100 b may operate as a controller of theXR device 100 a. To this end, the XR device 100 a may obtain informationabout a 3D position of the hand-held device 100 b and generate andoutput an XR object corresponding to the hand-held device 100 b.

Examples of a robot applicable to the present disclosure

FIG. 19 illustrates a robot applied to the present disclosure. The robotmay be categorized into an industrial robot, a medical robot, ahousehold robot, a military robot, etc., according to a used purpose orfield.

Referring to FIG. 19, a robot 100 may include a communication unit 110,a control unit 120, a memory unit 130, an I/O unit 140 a, a sensor unit140 b, and a driving unit 140 c. Herein, the blocks 110 to 130/140 a to140 c correspond to the blocks 110 to 130/140 of FIG. 15, respectively.

The communication unit 110 may transmit and receive signals (e.g.,driving information and control signals) to and from external devicessuch as other wireless devices, other robots, or control servers. Thecontrol unit 120 may perform various operations by controllingconstituent elements of the robot 100. The memory unit 130 may storedata/parameters/programs/code/commands for supporting various functionsof the robot 100. The I/O unit 140 a may obtain information from theexterior of the robot 100 and output information to the exterior of therobot 100. The I/O unit 140 a may include a camera, a microphone, a userinput unit, a display unit, a speaker, and/or a haptic module. Thesensor unit 140 b may obtain internal information of the robot 100,surrounding environment information, user information, etc. The sensorunit 140 b may include a proximity sensor, an illumination sensor, anacceleration sensor, a magnetic sensor, a gyro sensor, an inertialsensor, an IR sensor, a fingerprint recognition sensor, an ultrasonicsensor, a light sensor, a microphone, a radar, etc. The driving unit 140c may perform various physical operations such as movement of robotjoints. In addition, the driving unit 140 c may cause the robot 100 totravel on the road or to fly. The driving unit 140 c may include anactuator, a motor, a wheel, a brake, a propeller, etc.

Example of AI device to which the present disclosure is applied.

FIG. 20 illustrates an AI device applied to the present disclosure. TheAI device may be implemented by a fixed device or a mobile device, suchas a TV, a projector, a smartphone, a PC, a notebook, a digitalbroadcast terminal, a tablet PC, a wearable device, a Set Top Box (STB),a radio, a washing machine, a refrigerator, a digital signage, a robot,a vehicle, etc.

Referring to FIG. 20, an AI device 100 may include a communication unit110, a control unit 120, a memory unit 130, an I/O unit 140 a/140 b, alearning processor unit 140 c, and a sensor unit 140 d. The blocks 110to 130/140 a to 140 d correspond to blocks 110 to 130/140 of FIG. 15,respectively.

The communication unit 110 may transmit and receive wired/radio signals(e.g., sensor information, user input, learning models, or controlsignals) to and from external devices such as other AI devices (e.g.,100 x, 200, or 400 of FIG. 14) or an AI server (e.g., 400 of FIG. 14)using wired/wireless communication technology. To this end, thecommunication unit 110 may transmit information within the memory unit130 to an external device and transmit a signal received from theexternal device to the memory unit 130.

The control unit 120 may determine at least one feasible operation ofthe AI device 100, based on information which is determined or generatedusing a data analysis algorithm or a machine learning algorithm. Thecontrol unit 120 may perform an operation determined by controllingconstituent elements of the AI device 100. For example, the control unit120 may request, search, receive, or use data of the learning processorunit 140 c or the memory unit 130 and control the constituent elementsof the AI device 100 to perform a predicted operation or an operationdetermined to be preferred among at least one feasible operation. Thecontrol unit 120 may collect history information including the operationcontents of the AI device 100 and operation feedback by a user and storethe collected information in the memory unit 130 or the learningprocessor unit 140 c or transmit the collected information to anexternal device such as an AI server (400 of FIG. 14). The collectedhistory information may be used to update a learning model.

The memory unit 130 may store data for supporting various functions ofthe AI device 100. For example, the memory unit 130 may store dataobtained from the input unit 140 a, data obtained from the communicationunit 110, output data of the learning processor unit 140 c, and dataobtained from the sensor unit 140. The memory unit 130 may store controlinformation and/or software code needed to operate/drive the controlunit 120.

The input unit 140 a may acquire various types of data from the exteriorof the AI device 100. For example, the input unit 140 a may acquirelearning data for model learning, and input data to which the learningmodel is to be applied. The input unit 140 a may include a camera, amicrophone, and/or a user input unit. The output unit 140 b may generateoutput related to a visual, auditory, or tactile sense. The output unit140 b may include a display unit, a speaker, and/or a haptic module. Thesensing unit 140 may obtain at least one of internal information of theAI device 100, surrounding environment information of the AI device 100,and user information, using various sensors. The sensor unit 140 mayinclude a proximity sensor, an illumination sensor, an accelerationsensor, a magnetic sensor, a gyro sensor, an inertial sensor, an RGBsensor, an IR sensor, a fingerprint recognition sensor, an ultrasonicsensor, a light sensor, a microphone, and/or a radar.

The learning processor unit 140 c may learn a model consisting ofartificial neural networks, using learning data. The learning processorunit 140 c may perform AI processing together with the learningprocessor unit of the AI server (400 of FIG. 14). The learning processorunit 140 c may process information received from an external devicethrough the communication unit 110 and/or information stored in thememory unit 130. In addition, an output value of the learning processorunit 140 c may be transmitted to the external device through thecommunication unit 110 and may be stored in the memory unit 130.

INDUSTRIAL APPLICABILITY

The above-described embodiments of the present disclosure are applicableto various mobile communication systems.

1. A method of operating a transmitting user equipment (TX UE) in awireless communication system, the method comprising: transmitting, bythe TX UE to a base station (BS), a request for a sidelink resource on afirst beam; and triggering, by the TX UE, first buffer status reporting(BSR), wherein the TX UE cancels the first BSR based on triggering ofbeam failure recovery (BFR) related to the first beam.
 2. The method ofclaim 1, wherein the TX UE triggers second BSR for first sidelink datarelated to the first BSR based on selection of a second beam by the BFR.3. The method of claim 2, wherein the TX UE transmits the second BSR tothe BS on the second beam.
 4. The method of claim 3, wherein the firstBSR occurs before the triggering of the BFR.
 5. The method of claim 4,wherein based on occurrence of second sidelink data after the triggeringof the BFR, the TX UE triggers third BSR by aggregating BSR informationfor the first sidelink data and BSR information for the second sidelinkdata, and wherein the second sidelink data is different from the firstsidelink data related to the first BSR.
 6. The method of claim 1,wherein the first sidelink data and the second sidelink data are relatedto a same destination identifier (ID).
 7. The method of claim 1, whereinthe first BSR is based on occurrence of first sidelink data to betransmitted by the TX UE to a receiving user equipment (RX UE).
 8. Themethod of claim 1, wherein a cell at a time that the first BSR istriggered is different from a cell at a time that a beam recovery isterminated.
 9. The method of claim 1, wherein the BFR is triggered basedon detection of beam failure by the TX UE more than a predeterminednumber of times.
 10. The method of claim 1, wherein a BFR timer startsupon the triggering of the BFR.
 11. The method of claim 1, wherein theTX UE is a Mode 1 user equipment (UE).
 12. A transmitting user equipment(TX UE) in a wireless communication system, the TX UE comprising: atleast one processor; and at least one computer memory operably connectedto the at least one processor and configured to store instructions that,when executed, cause the at least one processor to perform operationscomprising: transmitting, by the TX UE, a request for a sidelinkresource to a base station (BS) on a first beam; and triggering, by theTX UE, first buffer status reporting (BSR), wherein the TX UE cancelsthe first BSR based on triggering of beam failure recovery (BFR) relatedto the first beam.
 13. The TX UE of claim 12, wherein the TX UEcommunicates with at least one of another user equipment (UE), a UE orBS related to autonomous vehicles, or a network.
 14. A processorconfigured to perform operations for a transmitting user equipment (TXUE) in a wireless communication system, the operations comprising:transmitting, by the TX UE, a request for a sidelink resource to a basestation (BS) on a first beam; and triggering, by the TX UE, first bufferstatus reporting (BSR), wherein the TX UE cancels the first BSR based ontriggering of beam failure recovery (BFR) related to the first beam. 15.A computer-readable storage medium configured to store at least onecomputer program including instructions that, when executed by at leastone processor, cause the at least one processor to perform operationsfor a transmitting user equipment (TX UE), the operations comprising:transmitting, by a transmitting user equipment (TX UE), a request for asidelink resource to a base station (BS) on a first beam; andtriggering, by the TX UE, first buffer status reporting (BSR), whereinthe TX UE cancels the first BSR based on triggering of beam failurerecovery (BFR) related to the first beam.